Article 6 of the Bovine Tuberculosis (Attestation of the State and General Provisions) Order 1989 S.I. No. 308 of 1989, as amended, provides that the test to be used for the detection of bovine TB shall be the intradermal tuberculin comparative test using PPD or HCSM bovine and avian tuberculins or a test specified in an authorisation in writing by the Minister. In infected herds, a supplementary test — the gamma interferon assay which has been authorised by me as an approved test- may be used by the Veterinary Inspector to identify additional animals which may be infected by tuberculosis and, in such cases, animals positive to this test will also, ordinarily, be removed as reactors.
Article 8 of the Bovine Tuberculosis (Attestation of the State and General Provisions) Order 1989, (S.I. No. 308 of 1989), as amended, provides that, where an animal has given a positive result to a test, it shall not be tested again with tuberculin. The Order does allow for retesting of reactor animals for experimental purposes but such experimental testing e.g. for new test development and/or potency checking of tuberculins, does not change the status of the reactor animals nor delay their removal from the farm.
The results of tuberculin tests carried out by approved veterinary practitioners are interpreted by Veterinary Inspectors in my Department's local District Veterinary Offices. Having taken into consideration test results, epidemiological factors, clinical symptoms and any other information available, the veterinary inspector will deem an animal to be a positive reactor where he or she believes or suspects it is affected with or is capable of infecting other animals with bovine tuberculosis and it will be removed from the herd and slaughtered. There is no provision for appeal by the herd owner as the decision to remove a reactor is based on veterinary opinion that the animal is infected.
However, on occasion a farmer, a veterinary practitioner or a veterinary inspector may raise queries about the result of a test in a herd and whether or not a particular treatment of an animal or animals may have affected the test result. In such cases, the circumstances will be investigated by the Veterinary inspectorate and taken into consideration when arriving at a decision as to whether the animal should be deemed to be a reactor.